String geneChatName(String chatName) {
  if (chatName == null || chatName.isEmpty) {
    return "(^_^)";
  }

  chatName = chatName
      .replaceAll('\（', "")
      .replaceAll('\）', "")
      .replaceAll('\《', "")
      .replaceAll('\》', "");

  if (chatName.length == 2) {
    return chatName;
  }

  if (chatName.length > 2) {
    return chatName.substring(chatName.length - 2, chatName.length);
  }
  return "";
}
